Scale for drawing utensils.



H. WJENGBL.

SGALE FOR DRAWING UTENSILS. APPLICATION FILED NOV. 4, 1811.

i 1,061,994. iatgnted Ma 2ofi913.

UNITED STATES PATENT OFFICE.

HERMANN WILHELM ENGEL, 'OF HAMBURG, GERMANY.

Specification of Letters Patent.

SCALE FOR DRAWING UTENSILS.

Patented May 20, 1913.

' Application filed November 4, 1911. Serial No. 658,456. i

To all whom it may c0ncern Be it known that I, HERMANN \VILHELM ENGEL, a subject of the German Emperor, residing at Hamburg, Germany, have invented a new and Improved Scale for Drawing Utensils, of which the following is a specification.

This invention relates to a scale which-is adapted to he removably secured to the edge of a T-square, set square, triangle or similar drawing utensil. By the use of this scale the drawings can be executed on either an enlarged or reduced scale without the assistance of a separate scale, so that the work of the draftsman is greatly facilitated.

In the accompanying drawings: Figure 1 is a side view of a scale embodving my invention showing it applied to a triangle; Fig. 2 a side view of the triangle with the scale detached; Fig. 3 is a side view of one of the scale members; Fig. 4 a similar new of a second scale member; Fig. 5 a similar view of a third scale member; Fig. 6 an end view of the scale member shown in Fig. 3; Fig. 7 an enlarged cross section on line C'D, Fig. 1, and. Fig. 8 a similar section on line EF, Fig. 1.

The scale is made substantially U-shaped in cross sect-ion and is adapted to straddle the edges of a T-square, triangle or similar drawing utensil e. The scale is composed of as many separable members a a a as there" are working edges on said utensil, so that'it may be readily applied and removed. The drawing shows the invention applied to a triangle, the edges of which'are recessed along both faces to form tongues adapted to enter the U-shaped scales a a a", so that in this way the shanks Z) of the latter will be flush with the faces of the utensil. At one of the acute angles of the triangle 0, scales a a are provided with inwardly extending overlapping lugs m, m adapted to enter a slot or recess here formed in the corner of the triangle. In like manlitzr scales a are provided at the other acute angle with the overlapping lugs n, nadapted to enter a corresponding cr-rner recess. Lugs m, m and n, 02 are apertured as at t to receive locking pins carried by springs p, g which are secured to one of the faces of the triangle. At the right angle, scale a is pro-. vided with a lug 0 having slot 8,,Wl1lle scale adapted to engage slot 8 when the parts are.

assembled.

It will be seen that by the construction described, the triangle is reinforced at the corners, so that its most vulnerable parts are effectively protected. In dismembering the device, springs p, g are raised to lift their pins out of apertures t, scale a is removed and then scales a a? are successively Withdrawn in any order desired. To assemble the parts, the above manipulation is reversed as will be readily understood.

I claim:

1. A drawing utensil provided with a recess at one of its corners combined with a scale of U-shaped cross section adapted to straddle said utensil and having a lug adapted to enter said recess.

2. A drawing utensil provided with a tongued edge and a recessed corner combined with a scale of U-shaped cross sectionadapted to straddle saidedge and having a lug adapted to enter said corner.

3. A drawing utensil provided with corner recesses and springs having locking pins combined with scales of U-shaped cross section adapted to straddle said utensil and having apertured lugs adapted to enter the recesses and to be engaged by the pins.

4. A drawing utensil having recessed CO1 ners combined with a plurality of scales of U-shaped cross section having lugs adapted to enter said corners, one of said lugs having a slot while the adjoining end of the abutting scale is provided with a pin adapted to enter said slot.

Signed b me at Hamburg, Germany, this 25th day o October, 1911.

I-[ERMANN VVILHELM ENGEL.

\Vitnesses AUGUST A. VVENK, ERNEST H. L. MUMMENHOFF. I 

